Guilherme Ferreira Pena

Improvement of a popcorn population using selection indexes from a fourth cycle of recurrent selection program carried out in two different environments.

We estimated genetic gains for popcorn varieties using selection indexes in a fourth cycle of intrapopulation recurrent selection developed in the campus of the Universidade Estadual do Norte Fluminense. Two hundred full-sib families were obtained from the popcorn population UNB-2U of the third recurrent selection cycle. The progenies were evaluated in a randomized block design with two replications at sites in two different environments: the Colégio Estadual Agrícola Antônio Sarlo, in Campos dos Goytacazes, and the Empresa de Pesquisa Agropecuária do Estado do Rio de Janeiro (PESAGRO-RIO), in Itaocara, both in the State of Rio de Janeiro. There were significant differences between families within sets in all traits, indicating genetic variability that could be exploited in future cycles. Thirty full-sib families were selected to continue the program. The selection indexes used to predict the gains were those of Mulamba and Mock, Smith and Hazel. The best results were obtained with the Mulamba and Mock index, which allowed the prediction of negative gains for the traits number of diseased ears and ears attacked by pests, number of broken plants and lodging, as well as ears with poor husk cover. It also provided higher gains for popping expansion and grain yield than with the other indexes, giving values of 10.55 and 8.50%, respectively, based on tentatively assigned random weights.

Ganho genético avaliado com índices de seleção e com REML/Blup em milho-pipoca

The objective of this work was to compare four selection indices and the REML/Blup method in the evaluation of the predicted genetic gains for the characteristics of interest to the breeding program of the UENF 14 popcorn. Two hundred full-sib progenies were evaluated in one season, in two locations (North and Northwest Regions of the state of Rio de Janeiro, Brazil), with two replicates, totaling 800 observations. The characteristics evaluated were average plant height, average height of first ear insertion, final stand, tipping, stem diameter, prolificacy, grain yield and popping expansion. Among the selection indices tested, Mulamba & Mocks provided the best results for selection of full-sib progenies. The REML/Blup method proved to be very efficient, selecting progenies with high relative performance and better predicted genetic gains than those of the selection indices tested. The progenies selected using the REML/Blup method, for highest grain yield, are not the same as those selected for higher popping expansion. The Mulamba & Mock index and the REML/Blup method provide the best predicted gains for the UENF 14 population.

Optimizing the efficiency of the touchdown technique for detecting inter-simple sequence repeat markers in corn (Zea mays)

We evaluated the efficiency of the touchdown method to determine the ideal PCR conditions for distinct inter-simple sequence repeat primers for processing DNA from common corn, popcorn, sweet corn, and a Tripsacum-maize hybrid. Genomic DNA was extracted from eight accessions of corn: two of the dent type, one Tripsacum-maize hybrid, one sweet corn, one flint-type corn, and three popcorn. Fifteen inter-simple sequence repeat primers were used: (CT)(8)RC, (CT)(8)TG, (GA)(8)T, (GA)(8)YC, (CTC)(5)RC, (GTC)(6), (GA)(6)CC, (GT)(6)CC, (CAC)(3)GC, (AG)(8)YT, (AC)(8)T, (AC)(8)YG, (CT)(8)RG, (GGAT)(3)GA, and (GAA)(6)AA. The annealing temperature and the melting temperature for each primer were estimated using a formula for RW Genes products, or we used the temperatures indicated by the manufacturer (Invitrogen). The touchdown method was then applied to each primer, varying the number of final cycles (10 or 12) and the decrease in temperature (0.5 degrees or 1.0 degrees C intervals). The gels were compared, considering the revelation quality, band sharpness and the number of bands visualized. The touchdown-PCR method was more efficient for band amplification for most of the primers, especially at higher annealing temperatures. This type of system is useful for reducing the resources, time and effort needed for optimizing temperature conditions for a group of representative primers.

Breeding potential and genetic diversity of "Híbrido do Timor" coffee evaluated by molecular markers

AFLP, RAPD and SSR molecular markers were used to study the genetic diversity and genetic structure of the Hibrido de Timor germplasm. The principal coordinate analysis, UPGMA cluster analysis based on genetic dissimilarity of Jaccard, Bayesian model-based cluster analysis, percentage of polymorphic loci, Shannons information index and Nei gene diversity were employed to assess the genetic diversity. The analyses demonstrated a high genetic diversity among Hibrido de Timor accessions. UPGMA and Bayesian cluster analyses grouped the accessions into three clusters. The genetic structure of Hibrido de Timor is reported. The management of Hibrido de Timor germplasm variability and its potential use in breeding programs are discussed.

ASSESSMENT OF EST-SSR MARKERS FOR GENETIC ANALYSIS ON COFFEE ( 1 )

EST-SSR markers were used to investigate the genetic diversity among and within coffee populations, to explore the possibility of their use for fingerprinting of cultivars and to assist breeding programs. Seventeen markers, developed from ESTs (Expressed Sequence Tags) from the Brazilian Coffee Genome Project, were used. All markers showed polymorphism among the genotypes assessed. The average number of allele per primer was 5.1. The highest polymorphisms were found within C. canephora (88.2%) and rust-resistant varieties (35.3%). About 29.4% of the markers differentiated C. arabica from Hibrido de Timor; it was also possible to identify those closest and farthest from C. arabica. The analysis of population-grouped genotypes revealed a 64.0% genetic diversity among and a 36.0% genetic diversity within populations. The differentiation index was 0.637. Six markers distinguished four rust-resistance varieties, showing their fingerprinting potential. These results demonstrate the usefulness of EST-SSR markers for cross orientation, in diversity and introgression studies, and in genetic mapping.

Genetic characterization of an elite coffee germplasm assessed by gSSR and EST-SSR markers.

Coffee is one of the main agrifood commodities traded worldwide. In 2009, coffee accounted for 6.1% of the value of Brazilian agricultural production, generating a revenue of US

Molecular diversity in Coffea canephora germplasm conserved and cultivated in Brazil

6 billion. Despite the importance of coffee production in Brazil, it is supported by a narrow genetic base, with few accessions. Molecular differentiation and diversity of a coffee breeding program were assessed with gSSR and EST-SSR markers. The study comprised 24 coffee accessions according to their genetic origin: arabica accessions (six traditional genotypes of C. arabica), resistant arabica (six leaf rust-resistant C. arabica genotypes with introgression of Híbrido de Timor), robusta (five C. canephora genotypes), Híbrido de Timor (three C. arabica x C. canephora), triploids (three C. arabica x C. racemosa), and racemosa (one C. racemosa). Allele and polymorphism analysis, AMOVA, the Student t-test, Jaccards dissimilarity coefficient, cluster analysis, correlation of genetic distances, and discriminant analysis, were performed. EST-SSR markers gave 25 exclusive alleles per genetic group, while gSSR showed 47, which will be useful for differentiating accessions and for fingerprinting varieties. The gSSR markers detected a higher percentage of polymorphism among (35% higher on average) and within (42.9% higher on average) the genetic groups, compared to EST-SSR markers. The highest percentage of polymorphism within the genetic groups was found with gSSR markers for robusta (89.2%) and for resistant arabica (39.5%). It was possible to differentiate all genotypes including the arabica-related accessions. Nevertheless, combined use of gSSR and EST-SSR markers is recommended for coffee molecular characterization, because EST-SSRs can provide complementary information.

UENF 14: a new popcorn cultivar

This work aimed to characterize accessions that represent the C. canephora germplasm conserved and cultivated in Brazil. A total of 130 accessions from germplasm banks of IAC (Sao Paulo), UFV (Minas Gerais) and also collected in plantations of the State of Espirito Santo and Rondonia were evaluated with a set of 20 new microsatellite primers. Multivariate methods were used to estimate the relationship among the accessions. High level of polymorphism and two major diversity clusters were identified. First cluster was composed by the accessions conserved in the IAC and UFV collections and the second was formed by accessions collected in areas under cultivation. Accessions from Espirito Santo and Rondonia were clear separated, composing two subclusters. Despite the great polymorphism found in Brazilian plantations, the diversity may be increased, because a new threshold in the genetic gains is expected on breeding programs with the intensification of the use of conserved germplasm.

Popcorn germplasm resistance to fungal diseases caused by Exserohilum turcicum and Bipolaris maydis

The aim of this work is to present the features of the popcorn cultivar UENF 14, developed from five cycles of recurrent selection of the population UNB-2U, to the scientific community. The cultivar produces yields of 3047.58 kg ha-1 and has popping expansion of 35.69 mL g-1.

Comparison of testers in the selection of S3 families obtained from the UENF-14 variety of popcorn

Compared with the common corn, popcorn shows greater susceptibility to pests and diseases occurrence, being the use of resistant cultivars the most efficient strategy. In this regard, Germplasm Banks deserve special attention because they contain accessions that can be used as sources of resistance in breeding programs. The State University of Northern Rio de Janeiro (UENF) maintains a popcorn Germplasm Bank with accessions from tropical and temperate countries, including Diversity Centers for the species. In this study, we investigated the performance of 37 popcorn accessions landraces, hybrids, and inbreed lines ― from the Germplasm Collection of UENF’s Popcorn Breeding Program with respect to the fungal leaf diseases northern leaf blight (NLB) and southern leaf blight (SLB), PLANT BREEDING Article Popcorn germplasm resistance to fungal diseases caused by Exserohilum turcicum and Bipolaris maydis Railan do Nascimento Ferreira Kurosawa1, Marcelo Vivas1, Antonio Teixeira do Amaral Junior1, Rodrigo Moreira Ribeiro1*, Samila Barbosa Miranda1, Guilherme Ferreira Pena1, Jhean Torres Leite1, Freddy Mora2 1.Universidade Estadual do Norte Fluminense Darcy Ribeiro Centro de Ciências e Tecnologias Agropecuárias Laboratório de Melhoramento Genético Vegetal Campos dos Goytacazes (RJ), Brazil. 2.Universidade de Talca Instituto de Ciências Biológicas Talca Chile. *Corresponding author: rodrigo.moreira85@yahoo.com.br Received: Feb. 1, 2017 – Accepted: Apr. 10, 2017 caused by Exserohilum turcicum and Bipolaris maydis, aiming to select promising accessions for genetic resistance to be used in future crosses to generate new resistant cultivars for farmers. The dendrogram scattering by the UPGMA multivariate technique was efficient in discriminating resistant accessions. Satisfactory results were obtained for resistance to NLB in accessions L71, L75, L76, P7, and PARA-172, which can thus be considered remarkable sources of resistance. For resistance to SLB, the superior accessions that can be indicated as sources of resistance are ARZM-05083, ARZM-07049, and PARA-172.